oneenv v1.0.0

oneenv — parse .env files straight into your Go structs. Zero dependencies, pure stdlib.

type Config struct {
    Port   int                   `env:"PORT" default:"8080"`
    Host   string                `env:"HOST,required"`
    APIKey oneenv.Secret[string] `env:"API_KEY"`
    DB     DBConfig              `envPrefix:"DB_"`
}

cfg, err := oneenv.Parse[Config](oneenv.WithEnvFiles())

Highlights

• Straight to struct — a dotenv parser and an env-to-struct decoder behind one fast, cached API.
• Environment-aware file cascade — WithEnvFiles() layers .env, .env.local, .env.<env> and .env.<env>.local by APP_ENV/GO_ENV, like Rails and Next.js.
• Secrets — ,file reads a value from a path (Docker/K8s); ,secret + Redacted and the Secret[T] wrapper keep sensitive values out of logs and JSON.
• Slices of structs — repeated config from indexed keys (SERVER_0_HOST, SERVER_1_HOST, …).
• Hot reload — the oneenv/watch subpackage re-decodes on file change via native OS notifications: inotify (Linux), kqueue (BSD/macOS), ReadDirectoryChangesW (Windows), with polling as a fallback — still zero external dependencies.
• Rich types — ints/floats/bool, time.Duration, time.Time, slices, maps, pointers, nested structs, and any encoding.TextUnmarshaler.
• Extensible — custom per-type parsers, value mutators and a pluggable validator, all dependency-free.
• Round-trips & help — Marshal renders a struct back to .env; Usage prints a --help table.
• Great errors — positioned parse errors (file:line) and every field failure collected at once via errors.Join.
• Hermetic tests — a Lookuper interface means no global state, parallel-safe by design.

Install

go get github.com/bakhod1r/oneenv@v1.0.0

Requires Go 1.26+.

See the CHANGELOG and README for full details.